1. Field of the Invention
The present invention relates to an image processing apparatus and, more particularly, to an image processing apparatus, an image capture apparatus and an input output apparatus all of which are constructed to perform brightness correction on images, as well as a processing method for these apparatuses and a program which causes a computer to execute the processing method.
2. Description of Related Art
Typically, in image capture apparatuses and image output apparatuses, processing for evaluating brightness of an original image through measurement and calculating a brightness correction amount on the basis of the resultant evaluation value have been performed in order to capture or output an image with appropriate brightness.
For example, many types of image capture apparatuses are provided with mechanisms for automatically controlling operations of their optical systems or their image sensors. Particularly, mechanisms for controlling the amount of exposure and adjusting the brightness of capture images are typically called Automatic Exposure (AE). An image capture apparatus having an AE mechanism includes a system for photometering the brightness of capture image data and performing exposure control on the basis of the measured brightness, in addition to a system for generating and outputting color image data with appropriate color and gradation by demosaicing, gamma correction, color correction and the like. In other words, in the image capture apparatus, a photometry evaluation value which evaluates the brightness of capture image data on the basis of a measured value of the brightness of each section of the capture image data is outputted and compared with a reference value indicative of standard brightness. Then, the amount of deviation between the photometry evaluation value and the reference value is calculated as a difference value, and the amount of aperture of a stop in the optical system, the charge storage time of a sensor, the amount of amplification of an amplifier and the like are adjusted in such a way that the difference values approaches 0, whereby the amount of exposure is controlled.
As such an AE mechanism, it has been proposed to provide a device which generates an integrated value of a luminance value of each of small areas into which the capture image data is divided, and performs weighted addition of the integrated luminance value to find the brightness evaluation value of the entire image. For example, an image processing apparatus has been proposed which divides the pixels of the entire picture of image data into a plurality of areas and finds a photometry value by using the central section of the image as the main area (refer to, for example, Japanese Patent Application Publication Number 2004-259177 (FIG. 1)).